Field control for wind driven generators



Jan. 25, 1944.

.L R. ALBERs 2,339,749

FIELUCONTROL PQR WIND DRIVEN GENERATORS Filed Da 22, 1941 IN VENTORPatented Jan. 25, 1944 CONTROL FOR WIND DRW'EN GENERATORIS John R.Albers, ySioux City, Iowa, assigner to Wincharger Corporation, SiouxCity, Iowa, a. corporation of Minnesota Application December 22, 1941,Serial N o. y11245030 6 Claims.

impellers, by matching as uniformly as possible the generator 'inputcurve to the impel'ler output curve, 'im-peller curve consisting ofpoints of maximam efficiency for the `various wind velocities,

' so Ithat the horse power input curve of the generato-r will vbecoincident 4with the horse power output curve of the 'impellen A furtherobject of my invention is to provide means whereby the 4charaoterlsticsof the generator are gradually and uniformly changed for the abovepurpose.

A further object v'of my invention is to provide means for graduallyy'and vuniformly inserting external resistance into `the generator fieldcircuit as the "iinpell'er *speed increases, and thence withdrawingsuch'resi-sta-nce'fromthe field 'as the propeller speed "increases4still further.

A fur-ther 4obj-ect of my invention is to provide a resistancelcontrolling mechanism which mechanism lcan vbe adjusted to provide thedesired amount of Iresistance to laccommodate any particular-generator-impeller combination.

With these and other objects in view, my invention :consists in theconstruction, varrangement, aand ktcombination of the various parts ofmy :devicefwhrereby the -obects 'contemplated are attained, fashereinater Amore *fully set forth, pointed ,fout in imy claims, landillustrated 'in the accompanying drawing, Ain which:

Aligure .1 isa :side elevation fof fa *wind operated charging :generatorof the typ-e 'useable with my invention,

Figure .2 is Aan enlarged detail of the operating mechanism,

Figure '3 is :a schematic view of the electr-ical circuit of thearrangement,

Figure -4 is Ta .chart 'of :typical curves for impellers and generatorstherefor.

My invention contemplates :the provision of means for .matching amaximumzeiiiciency 1impe1- 1er curve together with the generatorattached thereto as will be vvapparent from the :description whichfollows.

Wind driven impellers yof thetype used for driving generators havecertain xed characteristics wherein the :eiiciency of the 'bladerorpowergenier-ated' by the :impeller Vwill vary as the V.cube of the win-dvelocity. rlfhis is a :naturalfeunctionof wind forcesand A:cannot 4bealtered. Thek impeller powy y ei-curve will be indicated generally as:shown Iin Figure 4 wherein the dotted line indicated bythe character IGrepresents the points of maximum power eiliciency of a typical impellervin various wind velocities wherein the vertical ordinates representshorse power and the horizontal ordinates `represents revolutions perminute of the impeller. The various curves determining the power outputin revolutions per minute are indicated by the solid lines character Il,it being noted that the curve I intersects these `lines at theirAmaximum points, or at the `points of maximum eiciency or horse powerfor the given Wind speed.

A typical generator curve is indicated by the character 'I2 or by theline including the elongated dash portions `and short dash portions.Usually only two Ypoints 'such as I3 and I4 `will be co incident on thelcurves I2 and I0. However, the objective is to carry the 'line I2 overto and coincident with the curve I0 throughout in order to obtain lthebest possible results and to provide generator input characteristicswhich match the impeller power output characteristics. This will thenallow the mpeller to give up its maximum amount of power at any certainwind velocity due to the generator horse power requirement beingidentical to that which the 'impeller is best capable .of producing.

.I .have further used the character I5 to designate an impellercomprising a pair of blades attached to a shaft I6 which drives therotor Il rotatably secured in a suitable generator lcasing I3 have thefield poles I9. Attached at the rear end of the generator casing I8 is acylindrical housing which is attached by means of a `iiange 2l to theilange 22 of the generator casing I8. The casing 20 can be sutiablymounted on the turntable 23 and attached at the rear of the .casing '218to the flanged portion '24 thereof is a tai-l vane supporting flange towhich is attached at 26 the rearwardly extending angle member 2l towhich :is attached at 28 the sheet metal vane29, saidvane being adaptedto maintain the impeller blades I"5 directly into the wind. The roto-rI1 is attached `to-a shaft T30 `which is rotatably received withintheilanges l2| and `22 Aand attached to the shaft 30 are the vears 3| fromwhich are pivoted links 32 Ywhich links are attached to the .fly balls33.

Attached to the balls 33 are the ears 3'4 from which are attachedfurther "links V:iii which links are pivotedto ears at 36 which ears areattached to the collar 31 which collar 31 is adapted to slide yalong theshaft 30. Attached at 38 to the 'collar 31. isthepost 39 whichterminates in a cam 40 which cam includes the lower cam surface 4|having the certain characteristics which will be described. Attached at42 to the wall 24 is a carbon pile resistor casing 43 which receives thecarbon discs 44 said discs being actuated for snug or loose engagementby means of a plunger 45 which is pivoted at 46 to a rocker arm 41 whichAarm 41 extends into a further portion 48 at the termination of which ismounted the small roller 49 which roller bears against the cam surface4I. The rocker arm 41 is pivoted at 5B to a bracket which is attached tothe resistor casing 43 and a tension spring 52 is attached at 53 to therocker arm 41 and to the resistor casing 43,

Receiving the shaft is the helical compression spring 54 which ispositionedv between the collar 31 and the ears 3|.

It will now be noted from the foregoing description that when the speedof rotation of the impeller 5 attains a predetermined R. P. M. the balls33 will be centrifugally urged outwardly and to the left as viewed inFigure 2 thereby carrying the collar 31 toward the left as well as theearn lDue to the engagement of the cam surface 4| .i

with the roller 49 this movement will correspondingly cause the rockerarm 41 to rotate slightly in a counter-clockwise direction and willthereby release the pressure of the plunger on the carbon pile 44 whichinserts a varying resistance in the eld circuit I9 as shown by thediagram in Figure 3. At the lowest point of the curve 4| the pressure onthe carbon discs will be the least, and the resistance will be thegreatest. However, as the speed of the impeller increases still -1further, the roller 49 will then continue to bear against the higherportions of the cam whereby the rocker arm 41 will be drawn by thespring 52 carrying the plunger 45 against the carbon pile and therebyreducing the resistance in the field circuit I9. Thus, the resistance isinserted in the iield as the speed increases and is then reduced as thespeed continues to increase above a predetermined point.

The cam surface 4| is formed of a suitable con- 1 tour to provide therequired resistance at the points corresponding to the loci of thepoints of the dotted line l0 in Figure 4 so that the horse powercharacteristics of the generator will follow directly the curve I0 ofthe propeller, thereby providing the results desired in a gradual anduniform change in the generator necessary to match the impeller outputcharacteristics.

It will now be seen that I have provided all of the advantages set forthin the object of my invention with further advantages being readilyapparent.

Some changes may be made in the construction and arrangement of theparts of my invention without departing from the real spirit and purposeof my invention and it is my intention to cover by my claims anymodified forms of structure or use of mechanical equivalents which maybe reasonably included within their scope.

I claim as my invention:

1. The method of controlling an impeller driven electrical generatingunit which comprises operating the generator of such unit at low windvelocities with very little external resistance in the field circuitthereoi', then, at velocities above a predetermined lower value, ingradually inserting resistance in the said field circuit to permit theimpeller to carry its load eiliciently at wind velocities increasingabove the predetermined lower value, and in then gradually decreasingthe resistance in said field circuit as the wind velocity continues toincrease still further above the predetermined lower value.

2. A mechanism for controlling an impeller driven electrical generatingunit which comprises means for operating the generator of such unit atlow wind velocities with very little external resistance in :the fieldVcircuit thereof, means for gradually inserting resistance in the saideld circuit at velocities above a predetermined lower value to permitthe impeller to carry its load efficiently at wind velocities increasingabove the predetermined lower value, and means for gradually decreasingthe resistance in said iield circuit as the wind velocity continues toincrease still further above-the predetermined lower value, said lasttwo means including a ball governor attached to the generator shaft, aresistor adjacent thereto, means actuating said resistor and cooperantwith said ball governor to gradually increase the resistance in said eldcircuit at said speeds increasing above said predetermined lower value,and thence gradually decrease said resistance as the said speedcontinues to increase still further above the predetermined lower value.

3. A mechanism for controlling an impeller driven electrical generatingunit which comprises means for operating the generator of such unit atlow wind velocities with very little external resistance in the eldcircuit thereof, means for gradually inserting resistance in the saidfield circuit at velocities above a predetermined lower value to permitthe impeller to carry its load eiliciently at wind velocities increasingabove the predetermined lower value, and means for gradually decreasingthe resistance in said eld circuit as the wind velocity continues toincrease still further above the predetermined lower value, said lasttwo means including a ball governor attached to the generator shaft, aresistor adjacent thereto, means actuating said resistor and cooperantwith said ball governor to gradually increase the resistance in said eldcircuit at said speeds increasing above said predetermined lower value,and thence gradually decrease said resistance as the said speedcontinues to increase still further above the predetermined lower value,said actuating means including a cam surface attached to said ballgovernor, said resistor unit being cooperatively engaged with said camsurface to vary the resistance in the eld circuit according to thepredetermined necessary values for correlating the impeller output withthe generator input at all speeds thereof.

4. A mechanism for controlling an impeller driven electrical generatingunit which comprises means for operating the generator of such unit atlow wind velocities with very little external resistance in the iieldcircuit thereof, means for gradually inserting resistance in said fieldcircuit at velocities above a predetermined lower value in such amountsas to cause the impeller to carry its load eiiiciently at windvelocities increasing above the predetermined lower value, and means forgradually decreasing the resistance in said eld circuit as the windvelocity continues to increase still further above the predeterminedlower value, said last two means including a ball governor attached tothe generator shaft, a resistor adjacent thereto, means actuating saidresistor and cooperant with said ball governor to gradually increase theresistance in said iield circuit at said speeeds increasing vabove apredetermined lower value, and thence gradually decreases saidAresistance as4 the said speed continues to increase still further abovethe predetermined lower value, said actuating means including a camsurface attached to said ball governor, said resistor unit beingcooperatively engaged with said cam surface to vary the resistance inthe field circuit according to the predetermined necessary values forcorrelating the impeller output with the generator input at all speedsthereof, said resistor including a carbon pile, and means for operatingsaid carbon pile from said cam surface to provide snug or looseengagement thereof.

5. Apparatus for controlling an impeller driven electrical generatingunit comprising a generator driven by a wind impeller, and means foroperating said generator at low wind velocities with small externalresistance in the field circuit of said generator, for graduallyinserting resistance in said field circuit at velocities above apredetermined lower velocity to cause the impeller to transfer energyefficiently from the wind to said generator at velocities above saidpredetermined lower velocity, and for gradually decreasing theresistance in said eld circuit as the Wind velocity continues toincrease still further above said predetermined lower velocity.

6. Apparatus for controlling an impeller driven electrical generatingunit comprising a generator driven by a wind impeller, and centrifugalmeans for operating said generator at low wind velocities with smallexternal resistance in the eld circuit of said generator, for graduallyinserting resistance in said eld circuit at velocities above apredetermined lower velocitlr to cause the impeller to transfer energyefficiently from the wind to said generator at velocities above saidpredetermined lower velocity, and for gradually decreasing theresistance in said eld circuit as the wind velocity continues toincrease still further above said predetermined lower velocity.

JOHN R. ALBERS.

